camt053-loader-mt942

Converts legacy SWIFT MT942 interim transaction reports into the camt053 model as ISO 20022 camt.052 account reports.

Contents

Getting started

• Install — pip install, one runtime dependency
• Requirements — toolchain floor, platforms
• Quick Start — one call from MT942 text to a camt.052 ParsedDocument

The camt053-loader-mt942 ecosystem

• The camt053-loader-mt942 ecosystem — the six packages of the camt053 suite

Library reference

• Capabilities at a glance — the current surface by theme
• Ecosystem comparison — short matrix; full table at docs/COMPARISON.md
• Benchmarks — headline numbers; full table at docs/BENCHMARKS.md
• Features — module-level capability list
• Configuration — core options
• Examples — runnable example index

Operational

• When not to use camt053-loader-mt942 — limitations
• Development — make targets, fuzzing, CI
• Security — guarantees and compliance
• Documentation — all reference docs
• Stability guarantees — SemVer axis, output stability, minimum toolchain discipline
• License

Install

As a Python library

pip install camt053-loader-mt942

Latest release: v0.0.23. SWIFT MT942 (the intraday sibling of MT940) is scheduled for retirement in November 2028. This loader covers the window where banks still produce MT942 but downstream tooling expects camt.052.

The package pulls in camt053 and has no other runtime dependency. It is pure Python and runs wherever camt053 does.

Requirements

• Python 3.10 or newer, tested in CI on 3.10, 3.11, 3.12, 3.13 and 3.14 on Linux (toolchain policy).
• camt053 0.0.23 or newer, below 1.0. The camt053 suite releases at one version, so install the matching camt053 release alongside this one.

Quick Start

from camt053_loader_mt942 import parse_mt942

mt942 = """:20:INTRA-REF-1
:25:COBADEFFXXX/DE89370400440532013000
:28C:42/1
:34F:EURD1000,00
:34F:EURC500,00
:13D:2606211430+0200
:61:2606210621CR500,00NMSCREF1//CREF1
:86:Customer payment for invoice 123
:61:2606210621D200,00NMSCREF2//CREF2
:86:Card settlement
:90D:1EUR200,00
:90C:1EUR500,00
"""

document = parse_mt942(mt942)

print(document.message_type)                # camt.052.001.08
print(document.msg_id)                      # INTRA-REF-1
print(document.statements[0].account.iban)  # DE89370400440532013000
print(document.creation_date_time)          # 2026-06-21T14:30:00+02:00

parse_mt942 returns a camt053.models.ParsedDocument, the same shape the camt053 camt.052 XML parser produces, tagged camt.052.001.08. Every consumer in the suite (the Excel writer, the validator, the MCP and LSP servers) reads it unchanged. A malformed or incomplete report raises ValueError naming the field.

The camt053-loader-mt942 ecosystem

camt053-loader-mt942 is one of six independently installable packages built around the camt053 ISO 20022 cash-management library. The suite ships one version number across all six and releases them together, core first; a scheduled job compares every member against PyPI.

flowchart LR
    A["MT942 text"] -->|parse_mt942| B["camt053-loader-mt942"]
    B -->|ParsedDocument (camt.052)| C["camt053"]
    C -->|writer / validator / MCP / LSP| D["Downstream consumers"]

Capabilities at a glance

Ecosystem comparison

The suite reads interim and end-of-day reports through one model. What each entry point accepts and produces, from each package's source:

See docs/COMPARISON.md for the evidence and complete matrix.

Benchmarks

Parse time grows linearly with both entries per report and reports per file; the growth exponent is the number to read. Measured with python benches/bench_parse_mt942.py on 2026-10-20.

See docs/BENCHMARKS.md for methodology and full results.

Features

The public API is one function, camt053_loader_mt942.parse_mt942(text). Each MT942 tag maps onto the camt053 model:

• Reversals. A :61: mark of RD (reversal of debit) or RC (reversal of credit) sets Entry.reversal_indicator=True.
• Unknown tags are ignored, so a future SWIFT addition does not break parsing.
• Interim reports carry no booked balances. MT942 has no :60F: / :62F:. It reports movements above a floor limit (:34F:) and the number and sum of debit and credit movements (:90D: / :90C:), which camt.052 holds in <Lmt> and <TxsSummry>.
• Model limitations. The camt053 model is statement-oriented: it has no field for <Lmt>, <TxsSummry>, an integer entry count, or an entry-level AddtlNtryInf. Rather than invent fields or drop data, the loader puts floor limits and summaries on Statement.balances with the proprietary codes above (the :90x: count follows the colon), and :61: supplementary details on the entry's details list, ahead of any :86: text. Consumers that expect only booked balances (OPBD, CLBD) can filter the proprietary codes by prefix.

Configuration

None. parse_mt942 takes the payload and no options, reads no environment variables and touches no files or network.

Examples

• examples/01_minimal_parse.py: the smallest valid MT942, parsed and inspected (the demo above).
• examples/02_round_trip_to_dict.py: MT942 in, camt053 to_dict() JSON out, the same shape a camt.052 XML source produces.
• benches/bench_parse_mt942.py: parse throughput along the two axes that grow in production.

CI runs every example and the benchmark (--quick) on every change.

When not to use camt053-loader-mt942

• You already receive camt.052 XML. Parse it with the camt053 core; this loader is the bridge for MT942-only sources.
• You need MT940 (end-of-day statements). Use camt053-loader-mt940.
• You need bank-specific :86: sub-fields (for example ?20 / ?30 structures). The raw :86: text is preserved in TransactionDetails.additional_info for you to parse downstream.
• Your MT942 arrives encrypted or inside a SWIFT FIN envelope. Decrypt and unwrap upstream and pass the report text.
• You need first-class camt.052 <Lmt> or <TxsSummry> fields. The model carries them as proprietary balance codes (see Features).

Development

git clone https://github.com/sebastienrousseau/camt053-loader-mt942
cd camt053-loader-mt942
python -m venv .venv && . .venv/bin/activate
make dev      # hash-pinned toolchain from requirements/ci.txt, package editable
make check    # every CI gate
make demo     # re-render .github/demo.gif (needs vhs)

make check runs ruff (lint and format), mypy in strict mode, pytest with a 100% line and branch coverage gate, the 100% docstring gate, the complexity ceilings against complexity-baseline.json, reuse lint, the version-source check, the benchmark and the examples. CI also runs the test matrix on Python 3.10 to 3.14, pip-audit over the pinned requirements, CodeQL, OpenSSF Scorecard, Atheris fuzzing of parse_mt942 (two minutes per change, 30 minutes weekly) and a daily suite-consistency check against PyPI. Hypothesis property tests in the suite assert the same contract: a document or a ValueError, never another exception. See CONTRIBUTING.md.

Security

The whole attack surface is the text the parser is handed. MT942 is a flat text format with no XML envelope, so the XXE and entity-expansion surface lives in the camt053 core (defusedxml and its XML guard), not here. Field regexes are anchored, and parse time is linear in input size (see Benchmarks). A malformed report raises ValueError rather than returning partial data, and fuzzing (Atheris, coverage-guided, on every change) holds the parser to raising nothing else. Releases are built by a hash-pinned toolchain from a signed tag and published with PyPI trusted publishing, SLSA build provenance and keyless sigstore signatures.

Report vulnerabilities according to SECURITY.md.

Documentation

User manual · API reference: parse_mt942 · Developer guide · Family map · Benchmarks · Toolchain policy · Changelog

Stability guarantees

The project is pre-1.0 and versions advance in 0.0.1 steps, in lockstep with the camt053 suite. The breaking axis is the document parse_mt942 returns: which fields a tag fills, the proprietary type_code values, the message_type, and which inputs raise. A change to any of these is breaking even when the function signature does not move, and is called out in the changelog; 0.0.23 changes where :61: supplementary details land. The Python floor moves only as described in the toolchain policy.

License

This project is dual-licensed under either:

• Apache License, Version 2.0 (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT License (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option. Dependencies keep their own licences.